Method for hydrophobic and oleophobic modification of polymeric materials with atmospheric plasmas

Abstract

A method of fabricating hydrophobic and oleophobic polymer fabric through two stages of modification using atmospheric plasmas including (a) moving a substrate into an atmospheric plasma area, generating an atmospheric filamentary discharge plasma with a first plasma working gas to obtain a first rough surface of said substrate, (b) exposing plasma treated substrate to air to obtain highly active peroxide on said first rough surface of said substrate, (c) immersing said substrate in a solution of fluorocarbon compound and processing a first stage of graft of a fluorocarbon monomer or oligomer on said substrate to obtain a grafted fluorocarbon monomer or oligomer layer on said first rough surface of said substrate, (d) processing a second stage of graft a fluorocarbon functional group to said grafted fluorocarbon monomer or oligomer layer by generating a carbon tetrafluoride plasma from a second plasma working gas and irradiating said carbon tetrafluoride plasma on said grafted fluorocarbon monomer or oligomer layer; and (e) curing and drying said substrate.

What is claimed is: 
     
       1. A method for fabricating a structure of a polymeric material having a hydrophobic and oleophobic modification by using atmospheric plasmas, comprising steps of:
 (a) moving a substrate into an atmospheric plasma area, generating an atmospheric filamentary discharge plasma with a first plasma working gas, irradiating said atmospheric filamentary discharge plasma on a surface of said substrate to activate and roughen said surface to obtain a first rough surface on said substrate, and adjusting roughness of said first rough surface of said substrate by adjusting a power density of said atmospheric filamentary discharge plasma and adjusting a period of time of said irradiating of said atmospheric filamentary discharge plasma; 
 (b) exposing said substrate to air after being irradiated by said atmospheric filamentary discharge plasma to obtain highly active peroxide on said first rough surface of said substrate; 
 (c) immersing said substrate in a solution of a fluorocarbon compound and processing a first stage of graft of a fluorocarbon monomer or oligomer on said substrate to obtain a grafted fluorocarbon monomer or oligomer layer on said first rough surface of said substrate, wherein said grafted fluorocarbon monomer or oligomer layer has a second rough surface having the same roughness as that of said first rough surface of said substrate; 
 (d) processing a second stage graft of a fluorocarbon functional group to said grafted fluorocarbon monomer or oligomer layer by generating a carbon tetrafluoride plasma from a second plasma working gas and irradiating said carbon tetrafluoride plasma on said grafted fluorocarbon monomer or oligomer layer to obtain a grafted fluorocarbon functional group layer on said grafted fluorocarbon monomer or oligomer layer; and 
 (e) curing and drying said substrate to generate cross-links in both said grafted fluorocarbon monomer or oligomer layer and in said grafted fluorocarbon functional group layer and between said grafted fluorocarbon monomer or oligomer layer and said grafted fluorocarbon functional group layer. 
 
     
     
       2. The method according to  claim 1 , wherein, in step (a), said substrate is a polymeric fabric selected from a group consisting of polypropylene (PP) fabric, polyethylene (PE) fabric, polyethylene terephthalate (PET) fabric, polyamide (PA) fabric and cotton fabric. 
     
     
       3. The method according to  claim 1 , wherein, the step (a), is carried out by roll-to-roll substrate moving. 
     
     
       4. The method according to  claim 1 , wherein, in step (a), said atmospheric filamentary discharge plasma is obtained from said first plasma working gas under pressure of one atmosphere. 
     
     
       5. The method according to  claim 1 ,
 wherein, in step (a), said first plasma working gas is a mixture of oxygen (O 2 ) and a gas selected from a group consisting of helium (He) and argon (Ar); 
 wherein said O 2  has a density to said gas not smaller than 10 persents (%). 
 
     
     
       6. The method according to  claim 1 , wherein, in step (a), said power density is not smaller than 0.9 W/cm 2 . 
     
     
       7. The method according to  claim 1 , wherein, in step (a), said first rough surface of said substrate is hydrophilic and has a roughness not smaller than 20 nm. 
     
     
       8. The method according to  claim 1 , wherein, in step (a), said atmospheric filamentary discharge plasma is irradiated on said substrate for a period of time between 3 and 5 min. 
     
     
       9. The method according to  claim 1 , wherein, in step (c), said fluorocarbon compound is selected from a group consisting of perfluoroalkysilane, 1H,1H,2H,2H-perfluorooctyldimethyl chlorosilane (PFDMCS) and fluoroalkyl silane. 
     
     
       10. The method according to  claim 1 , wherein, in step (c), said substrate is immersed in the diluted solution of said fluorocarbon compound for graft of fluorocarbon monomers or oligomers for a period of time between 3 and 5 min. 
     
     
       11. The method according to  claim 1 , wherein, in step (d), said carbon tetrafluoride plasma is generated from said second plasma working gas under pressure of one atmosphere. 
     
     
       12. The method according to  claim 1 , wherein, in step (d), said second plasma working gas is a mixture of He and carbon tetrafluoride (CF 4 ); and wherein said CF 4  has a flow rate of 9:1 to He (CF 4 /He). 
     
     
       13. The method according to  claim 1 , wherein, in step (d), said power density is not smaller than 0.6 W/cm 2 . 
     
     
       14. The method according to  claim 1 , wherein, in step (d), said fluorocarbon functional group is grafted for 3 min.